Efficient recovery of zinc and copper from copper smelting slag (CSS) by cooperative modification with a composite medium of FeS-O2

Efficient recovery of valuable metals from copper smelting slag (CSS) can not only alleviate the pressure from resource scarcity, but also has important practical significance for the realization of green and sustainable production in the copper smelting industry. In this paper, a composite medium of FeS-O2 is used as a synergistic modifier to transform the solid-state valuable metals in CSS into leachable state of sulphates, and achieves efficient and comprehensive recovery of zinc and copper through neutral leaching. XRD, FTIR, XPS, etc and comparative analysis methods are used to deeply analyze the characteristics of occurrence phase and transformation rules of valuable metal in CSS, roasted slag and leached slag. The results show under the optimal roasting conditions of TRoasting = 650 degrees C, M(copper slag): M(FeS) = 1:1, V(O2): V(Ar) = 1:6 and tHolding = 90 min, the recovery rate for zinc is approximately 95.1 %, and that for copper is 99.3 %, almost all of which is recovered. These findings provide a new method and process foundation and theoretical support for the efficient resource utilization of CSS.